Stator structure for rotary electric machine

Abstract

This invention is to provide a stator structure for a rotary electric machine comprising poles of an armature core made of soft magnetic material and bobbins wound with coils at the respective poles and inserted into the poles in which the bobbin wound with the coils are mounted at the stator poles without decreasing motor characteristics. The material of a collar part (auxiliary pole tooth or extrapolation pole tooth) of a bobbin opposed to a rotor is formed of resin filled with soft magnetic material to improve the characteristics of a rotary electric machine. It is also effective to form the end of the collar part of the bobbin of a ferromagnetic material. Since a magnetic flux is also passed through the auxiliary pole tooth or the extrapolation pole tooth provided at the bobbin, the magnetic reluctance of the magnetic path to the rotary pole can be reduced. Further, the surface of the auxiliary pole tooth opposed to the rotary pole is formed in an arc shape along the inner periphery of the rotary pole, and a gap between the rotary pole and the auxiliary pole tooth is controlled.

What is claim is: 
     
       1. A motor structure for a rotary electric machine, comprising: a rotational shaft;   a rotary disk connected to said rotational shaft having rotary poles consisting of a ring-shared permanent magnet;   a ring-shaped yoke made of soft magnetic material disposed at a circumferential side of said rotational shaft;   stator poles made of soft magnetic material radially extending from said ring-shaped yoke to outside said yoke, said stator poles having a unitary body and facing said rotary poles;   a bobbin wound with windings such that the bobbin can be inserted with the windings into one of said stator poles;   wherein, said bobbin has a collar part facing said ring-shaded permanent magnet rotary pole at one end thereof; and   said collar part is formed of a material containing soft magnetic material; and   the bobbin is provided with a pair of terminals for windings at an end thereof opposite the collar part.   
     
     
       2. A motor structure for a rotary electric machine according to claim 1, wherein the entire bobbin is formed of a material containing soft magnetic material. 
     
     
       3. A motor structure for a rotary electric machine according to claim 1 or 2, wherein a material containing soft magnetic material is synthetic resin such as polymer material. 
     
     
       4. A motor structure for a rotary electric machine according to claim 1 or 2, wherein said soft magnetic material contained in said collar part is soft ferrite such as iron oxide. 
     
     
       5. A motor structure for a rotary electric machine according to claim 1, wherein a surface of said one end of said collar part facing said ring-shaped permanent magnet rotary pole is formed in an arc shape along an arc shape of said rotary pole. 
     
     
       6. A motor structure for a rotary electric machine, comprising: a rotational shaft;   stator poles made of soft magnetic material extending from a yoke in a perpendicular direction to said rotational shaft;   a rotary pole made of a ring-shaped permanent magnet surrounding said stator poles;   a bobbin wound with windings such that the bobbin can be inserted with the windings into one of said stator poles;   wherein, said bobbin has a collar part, formed of soft magnetic material facing said ring-shaped rotary pole at one end thereof;   an extrapolation pole tooth of ferromagnetic material fixed to a surface of said collar part facing said ring-shaped rotary pole; and   the bobbin is provided with a pair of terminals for windings at an end thereof opposite the collar part.   
     
     
       7. A motor structure for a rotary electric machine according to claim 1, wherein said bobbin has, at another end thereof, another collar part to contact closely with said yoke, said another collar part having said pair of terminals for windings. 
     
     
       8. A motor structure for a rotary electric machine according to claim 7, wherein said bobbin is formed of polymer having no magnetic material therein. 
     
     
       9. A motor structure for a rotary electric machine according to claim 1, wherein said rotary electric machine is an outer rotor type brushless DC motor. 
     
     
       10. A motor structure for a rotary electric machine according to claim 9, wherein the entire bobbin is formed of a material containing soft magnetic material.